Gating of the afferent volley of the monosynaptic stretch reflex during movement in man.

摘要: 1. The time course of the changes in presynaptic inhibition Ia fibres to soleus motoneurones has been investigated during a voluntary ramp-and-hold plantar flexion. 2. Monosynaptic facilitation H reflex was evoked by stimulation inferior (homonymous) and femoral (heteronymous) nerves. Changes mediating conditioning volleys were inferred from amount such constant stimulations. 3. At beginning contraction, both homonymous heteronymous facilitations markedly increased with respect their rest values. Then, they dropped abruptly middle ramp, whatever ramp duration. 4. stronger contraction at end larger initial increase facilitation. 5. These results indicate that terminals on contracting muscle is decreased first half then returns its level. It argued these are centrally programmed, it suggested that, under certain conditions, can be modulated according strength timing contraction. 6. functional role resulting gain stretch discussed.